A new building for a university near Chicago, Illinois, US, utilizes a hybrid advanced natural ventilation strategy to condition a deep-plan library. The design and construction are described, but the paper focuses on the post-construction, pre-occupancy commissioning trials undertaken to test both the active and passive environmental control systems. These simple qualitative trials confirmed that the advanced natural ventilation strategy functioned broadly as intended, but reveal unexpected features of the mechanical systems, faulty components, errors in the control logic of the building management system, and design omissions. Many of these could be readily corrected before occupancy, thereby improving the likely energy and environmental performance. The trials highlighted the need for forms of contract and methods of working that enable the integrated working of design teams, especially when designing innovative buildings. The benefits of adopting simple qualitative commissioning trials, and some of the current barriers to achieving this, are discussed.